It takes Ann, brad and chad two hours to paint a fence. When Ann works alone , she can paint the same fence in six hours. When brad works alone , he can paint the same fence in four hours. How long would it take for chad to paint the same fence on his own
+36916 1/a + 1/b + 1/c = 1/2
1/6 + 1/4 + 1/c = 1/2 solve for 'c' the time of chad alone
2/12 + 3/12 + 1/c = 1/2
1/c = 1/2 - 5/12
1/c = 1/12
c = 12 hours
